New In A Light - A Coating That Heals In Light

Wouldn't it be great if you could take your car to the panel shop and have it repaired in minutes, before your eyes, without anyone even laying hands on it? Wouldn't you love to have a tabletop that could handle a gouging from a wayward knife or ballpoint pen? Wouldn't it be wonderful if you only ever had to buy Tupperware once?

There have been several developments in self-healing coatings recently, but the latest innovation from a collaboration between Ohio's Case Western Reserve University, Switzerland's University of Fribourg, and the Army Research Laboratory in Maryland has to be one of the best yet.

While most self-healing coatings require heat to heal, all this one requires is light, and it does it fast.

The 'optically healable supramolecular polymers' actually disassemble when exposed to a high dose of ultraviolet light. The light causes the metallosupramolecular polymer's molecules to become electrically excited, which generates heat, causing the non-covalently linked, low-molecular-mass polymers to become temporarily disengaged. Once disengaged from the scratched chaos, they link back into the original structure of their coordination complex.

Or, as co-author Christoph Weder, from the University of Fribourg, puts it, "Ultraviolet light is absorbed by the sticky end groups of our new
supramolecular polymers, converted into heat, and the supramolecular
structures disassemble into the small building blocks from which they
were made."

But what is the advantage of using light instead of heat to heal a material? Fellow researcher, Mark Burnworth, from Case Western Reserve, explains: "By using light, we have more control as it allows us to target only the defect and leave the rest of the material untouched.”